Wireless communication systems, for example cellular telephony or private mobile radio communication systems, typically provide for radio telecommunication links to be arranged between a plurality of end devices via a system infrastructure having fixed installations including one or more base transceiver stations (base stations).
In many public service environments, the end devices communicate through digital push-to-talk (PTT) connections. Different types of PTT connections are used, depending on the standard(s) supported by the devices and network. These connection types include direct communication between the end devices, in which system infrastructure is not used, or indirect communication between the end devices, in which the system infrastructure is employed. A variety of modes may be used in each of these communications types, which include conventional over-the-air (OTA) device-to-device communication or trunked communication in which a multicast (talk) group is initially established and then transmissions sent to all end devices that are members of the talkgroup.
In infrastructure-based PTT communications, the call from the transmitting end device (hereinafter referred to as the transmitter) is transmitted to the base station servicing the transmitter. This call is subsequently patched through a console to receiving end devices (hereinafter referred to as the receivers). The call from the transmitter operating using one type of communication (e.g., digital) may be patched through to one or more of the same or different communication types (e.g., digital, analog, trunked) by the console.
It is desirable for the receivers in a patched call, as well as other listening devices listening into the call (either audio or control information provided by the console), to be able to obtain the transmitter identity. Consoles have not previously had the capability to supply the transmitter identity when providing an audio patch, for example, to a trunking site controller where the control channel requires the identity of the transmitter (such as when using the APCO Project 25 (P25) Trunking CAI standard protocol). Accordingly, it would be desirable for the console to provide transmitter identity to the various target devices being supplied with call information when patching calls.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.